For ZIP and GZIP formats 7-Zip provides compression ratio that is 30-70 % better than ratio provided by PKZip and WinZip

Self-extracting capability for 7z format

Integration with Windows Shell

Powerful File Manager

Powerful command line version

Plugin for FAR Manager

Localizations for 74 languages

Installation

For 32-bit operating systems, run 7zip920-x86.exe. For 64-bit operating systems, run 7zip920-x64.msi

Welcome - Click Next

End-User License Agreement - Check I accept and click Next

Custom Setup - Disable Localization files and click Next

Ready to Install - Click Install

Setup Complete - Click Finish

ConfigurationNOTE: This process will configure Windows to automatically use 7-Zip if you double-click on an archive.

Start 7-zip File Manager (might need to "run as administrator")

Click Tools, Options

Under the System tab, place a checkmark beside 7z, rar and zip, click OK

Close 7-zip File Manager

Right-click on a small file, select Add to archive

Add to Archive - Set the following and click OK:Archive Format: 7zCompression Level: Ultra

Delete the zip file you just created. 7-Zip remembers the last setting you use and 7z with Ultra compression makes the smallest files.

File Compression BasicsWhen it's all said and done, I prefer 7-zip over everything else. It has the best compression, it's free, the source code is freely available and you can decompress all archives and create 7z or zip archives.

If you want the best compression to save space, download and upload time, use the .7z format.If you want the best speed during compression and best portability, use the .zip format. (good for small files so that even WinXP can open them)The .rar format is simply a middle-of-the-road format.

Most Common Archive Formats (2010)

Filetype extension: .7zCommonly referred to as: 7-zip (or SevenZip)Program Web site: www.7-zip.comCost: FREELicense: Open Source, GPLCompression: BestPortability: To extract files in this format, each use must have 7-zip or the latest version of WinRARNative Support in Windows XP?: No

Filetype extension: .rarCommonly referred to as: RARProgram web site: www.rarlabs.comCost: $30License: TrialwareCompression: Better than OKPortability: To extract files in this format, each user must have WinRAR, 7-zip, or simular compatible program.Native Support in Windows XP?: No

Filetype extension: .zipCommonly referred to as: ZipProgram Web Site: www.winzip.comCost: $30License: TrialwareCompression: OKPortability: This format has been around so long that just about every program that deals with compression can handle it.Native Support in Windows XP?: Yes